Radiation detection device

ABSTRACT

A radiation detection device includes: a radiation detection panel; a supporting member having a first surface and a second surface being opposite to the first surface, wherein the radiation detection panel is provided at a side of the first surface; an electronic component that is provided on the second surface of the supporting member and drives the radiation detection panel or processes an electric signal output from the radiation detection panel; and a housing that accommodates the radiation detection panel, the supporting member, and the electronic component, a bottom of the housing which faces the second surface comprises a flat portion and a slope portion that is adjacent to the flat portion and becomes closer to the second surface as becoming further away from the flat portion, and the electronic component is provided at a position as defined herein.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Japanese Patent Application JP2017-246639, filed Dec. 22, 2017, the entire content of which is herebyincorporated by reference, the same as if set forth at length.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a radiation detection device.

2. Description of the Related Art

A so-called flat panel detector (FPD) is used to acquire a radiographicimage of an object. The FPD comprises, for example, a scintillator thatemits fluorescence corresponding to the amount of incident radiation anda detection substrate on which pixels detecting the fluorescence emittedfrom the scintillator are two-dimensionally arranged. Radiationtransmitted through the object is incident on the scintillator and eachpixel converts the fluorescence generated from the scintillator into anelectric signal. Radiographic image data of the object is generated onthe basis of the electric signal output from each pixel. A so-calledelectronic cassette in which an FPD is accommodated in a housing andwhich is portable has been known as the radiation detection devicecomprising the FPD (for example, see JP2014-025847A).

A radiography apparatus disclosed in JP2014-025847A comprises aradiation detection panel which is an FPD, a signal processing substratewhich is a wiring substrate having various circuits mounted thereon, asupporting member on which the radiation detection panel and the signalprocessing substrate are provided, and a housing which accommodating theradiation detection panel, the signal processing substrate, and thesupporting member. The radiation detection panel is provided on anirradiation surface of the supporting member and the signal processingsubstrate is provided on a non-irradiation surface of the supportingmember. The radiation detection panel and the signal processingsubstrate are connected to each other by a flexible substrate that isbent so as to pass between a side surface of the supporting member and aside portion of the housing. An electronic component that performssignal processing is mounted on the flexible substrate. The electroniccomponent is provided at the edge of the non-irradiation surface of thesupporting member.

SUMMARY OF THE INVENTION

A portable electronic cassette can be placed at various locations andthen used. However, in a case in which the portable electronic cassettefalls down, an impact is likely to be applied to the portable electroniccassette. In the radiography apparatus disclosed in JP2014-025847A, theentire bottom of the housing is flat and the impact applied in a case inwhich the radiography apparatus falls down is mainly applied to the edgeof the bottom of the housing. The electronic component is provided so asto face the edge of the bottom of the housing. The thickness of theelectronic cassette is typically about 15 mm. In a case in which thereis a gap between the electronic component and the bottom of the housing,the gap is about several millimeters. Therefore, in a case in which thebottom of the housing is deformed by the impact applied to the edge ofthe bottom, the bottom of the housing comes into contact with theelectronic component and the impact is transmitted to the electroniccomponent. As a result, there is a concern that the electronic componentwill be damaged.

The invention has been made in view of the above-mentioned problems andan object of the invention is to provide a radiation detection devicethat can protect an electronic component from an impact applied in acase in which the radiation detection device falls down.

According to an aspect of the invention, there is provided a radiationdetection device comprising: a radiation detection panel; a supportingmember having a first surface on which the radiation detection panel isprovided; an electronic component that is provided on a second surfaceopposite the first surface of the supporting member and drives theradiation detection panel or processes an electric signal output fromthe radiation detection panel; and a housing that accommodates theradiation detection panel, the supporting member, and the electroniccomponent. A bottom of the housing which faces the second surfaceincludes a flat portion and a slope portion that is adjacent to the flatportion and becomes closer to the second surface as becoming furtheraway from the flat portion. The electronic component is provided at aposition where at least a center of gravity of the electronic componentoverlaps the slope portion.

According to the invention, it is possible to provide a radiationdetection device that can protect an electronic component from an impactapplied in a case in which the radiation detection device falls down.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating an example of a radiationdetection device for describing an embodiment of the invention.

FIG. 2 is a cross-sectional view illustrating the radiation detectiondevice taken along the line II-II of FIG. 1.

FIG. 3 is an enlarged view illustrating a portion surrounded by a dashedframe III illustrated in FIG. 2.

FIG. 4 is a diagram schematically illustrating the function of a slopeportion of the bottom of a housing illustrated in FIG. 2.

FIG. 5 is a cross-sectional view illustrating a main portion of anotherexample of the radiation detection device for describing the embodimentof the invention.

FIG. 6 is a diagram schematically illustrating a modification example ofthe radiation detection device illustrated in FIG. 5.

FIG. 7 is a diagram schematically illustrating another modificationexample of the radiation detection device illustrated in FIG. 5.

FIG. 8 is a cross-sectional view illustrating a main portion of stillanother example of the radiation detection device for describing theembodiment of the invention.

FIG. 9 is a cross-sectional view illustrating a main portion of yetanother example of the radiation detection device for describing theembodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 and 2 illustrate an example of a radiation detection device fordescribing an embodiment of the invention.

A radiation detection device 1 illustrated in FIGS. 1 and 2 is aso-called electronic cassette and comprises a radiation detection panel2 that detects radiation, such as X-rays, a supporting member 3, and ahousing 5 that accommodates the radiation detection panel 2 and thesupporting member 3.

The housing 5 is formed in a rectangular parallelepiped shape andtypically has a size based on the International Organization forStandardization (ISO) 4090:2001. It is preferable that the housing 5 ismade of a material which can reduce weight and increase load resistance.Examples of the material include a magnesium alloy, an aluminum alloy, afiber reinforced resin, a cellulose nanofiber (CNF) reinforced resin,and a resin that satisfy a specific gravity of 3.0 or less and a Young'smodulus of 1.8 GPa or more. A rectangular opening is formed in a topplate 6 of the housing 5. A transmission plate 7 that transmitsradiation is attached to the opening.

The radiation detection panel 2 includes a scintillator 8 and adetection substrate 9 and is provided behind the transmission plate 7 inthe housing 5. The scintillator 8 has a phosphor, such as CsI:Tl(thallium-activated cesium iodide) or GOS (Gd₂O₂S:Tb, terbium-activatedgadolinium oxysulfide), and emits fluorescence corresponding to theamount of incident radiation. The detection substrate 9 includes aplurality of pixels that are two-dimensionally arranged, detectsfluorescence generated by the scintillator 8 with the pixels, andconverts the detected fluorescence into an electric signal.

In this example, the scintillator 8 and the detection substrate 9 arestacked in the order of the scintillator 8 and the detection substrate 9from the transmission plate 7 of the housing 5. However, thescintillator 8 and the detection substrate 9 may be stacked in the orderof the detection substrate 9 and the scintillator 8 from thetransmission plate 7. In addition, a direct-conversion-type radiationdetection panel may be used in which a photoconductive film of eachpixel of the detection substrate 9 that generates signal charge is madeof, for example, amorphous selenium and which directly convertsradiation into signal charge.

The supporting member 3 is a plate-shaped member and is formed in arectangular shape. In the specification, the rectangular shape is notlimited to a quadrangle with right-angled corners and includes aquadrangle with chamfered corners or a quadrangle with rounded corners.The supporting member 3 has a first surface 10 that faces the top plate6 of the housing 5 and a second surface 11 that is opposite to the firstsurface 10. The radiation detection panel 2 is provided on the firstsurface 10 of the supporting member 3. In addition, the radiationdetection panel 2 may be attached to the supporting member 3 or may beattached to the top plate 6 and the transmission plate 7 of the housing5. It is preferable that the supporting member 3 is made of a materialwhich can reduce weight and increase load resistance. Examples of thematerial include a magnesium alloy, an aluminum alloy, a fiberreinforced resin, a cellulose nanofiber (CNF) reinforced resin, and aresin that satisfy a specific gravity of 3.0 or less and a Young'smodulus of 1.8 GPa or more.

A circuit substrate 12 and a power supply unit 13 are accommodated inthe housing 5. For example, a driving control circuit that controls thedriving of the detection substrate 9, a signal processing circuit thatprocesses the electric signal output from the detection substrate 9, acommunication circuit for communication with the outside, and a powercircuit are formed on the circuit substrate 12. The power supply unit 13supplies power to the detection substrate 9 and the circuit substrate12. The power supply unit 13 is a rechargeable battery, such as alithium-ion secondary battery, or a capacitor, such as an electricdouble layer capacitor or a lithium-ion capacitor. The circuit substrate12 and the power supply unit 13 are bonded to the second surface 11 ofthe supporting member 3.

The circuit substrate 12 is schematically illustrated as a singleelement in FIG. 2. However, the circuit substrate 12 may be divided intoa plurality of circuit substrates and the plurality of circuitsubstrates may be dispersed on the second surface 11 of the supportingmember 3. The power supply unit 13 is schematically illustrated as asingle element in FIG. 2. However, the power supply unit 13 may bedivided into a plurality of power supply units and the plurality ofpower supply units may be dispersed on the second surface 11 of thesupporting member 3.

A plurality of spacers 14 are provided on the second surface 11 of thesupporting member 3. The plurality of spacers 14 protrude from thecircuit substrate 12 and the power supply unit 13 and come into contactwith a bottom 15 of the housing 5 which faces the second surface 11. Thesupporting member 3 is supported by the plurality of spacers 14. Thereis a gap between the bottom 15 of the housing 5 and the circuitsubstrate 12 and the power supply unit 13.

The detection substrate 9 of the radiation detection panel 2 providedabove the first surface 10 of the supporting member 3 and the circuitsubstrate 12 provided on the second surface 11 of the supporting member3 are connected to each other by a flexible substrate 16. The flexiblesubstrate 16 is bent so as to pass between the supporting member 3 and aside portion 17 of the housing 5. One or more electronic components 18are mounted on the flexible substrate 16. The electronic component 18 isprovided at the edge of the second surface 11 of the supporting member3.

The electronic component 18 is, for example, a reading integratedcircuit (IC) that reads the signal charge (analog signal) output fromeach pixel of the detection substrate 9. The reading IC forms a portionof the signal processing circuit of the circuit substrate 12. Inaddition, the electronic component 18 may be a driving IC that controlsa signal charge accumulation operation, an output operation, and a resetoperation in each pixel of the detection substrate 9. The driving ICforms a portion of the driving control circuit of the circuit substrate12.

FIG. 3 is an enlarged view illustrating the surroundings of theelectronic component 18.

The bottom 15 of the housing 5 which faces the second surface 11 of thesupporting member 3 includes a flat portion 20 and a slope portion 21.The slope portion 21 is adjacent to the flat portion 20 and forms theedge of the bottom 15 of the housing 5. The slope portion 21 becomescloser to the second surface 11 as it becomes further away from the flatportion 20. The electronic component 18 provided at the edge of thesecond surface 11 of the supporting member 3 is disposed at a positionwhere at least the center of gravity O of the electronic component 18overlaps the slope portion 21. In this example, the electronic component18 does not come into contact with the flat portion 20 and the slopeportion 21.

FIG. 4 schematically illustrates the function of the slope portion ofthe bottom of the housing 5.

FIG. 4 illustrates a state in which the radiation detection device 1falls down and the bottom 15 of the housing 5 comes into contact with aninstallation surface S. The slope portion 21 becomes closer to thesecond surface 11 of the supporting member 3 as it becomes further awayfrom the flat portion 20. The flat portion 20 comes into contact withthe installation surface S and the slope portion 21 becomes further awayfrom the installation surface S as it becomes further away from the flatportion 20. In a case in which the radiation detection device 1 fallsdown and the bottom 15 comes into contact with the installation surfaceS, an impact is applied to a boundary portion 20 a of the flat portion20 with the slope portion 21.

Since the center of gravity O of the electronic component 18 is disposedat the position that overlaps the slope portion 21, the impact appliedto the boundary portion 20 a of the flat portion 20 is prevented frombeing directly transmitted to the electronic component 18. The impactapplied to the boundary portion 20 a of the flat portion 20 is dispersedto the flat portion 20 and the slope portion 21. Even in a case in whichthe impact dispersed to the slope portion 21 is transmitted to theelectronic component 18, the impact transmitted to the electroniccomponent 18 is a portion of the impact applied to the boundary portion20 a of the flat portion 20 and is reduced. Therefore, it is possible toprevent the damage of the electronic component 18 and to prevent noisefrom being superimposed on the electronic component 18. The amount ofnoise superimposed in analog signal processing is significantly morethan the amount of noise superimposed in digital signal processing. Thisconfiguration is particularly useful in a case in which the electroniccomponent 18 processes analog signals. In addition, the analog signalprocessing includes the conversion of an analog signal into a digitalsignal.

Preferably, as illustrated in FIG. 3, the slope portion 21 includes aportion that is provided between the boundary between the flat portion20 and the slope portion 21 and a position that overlaps the center ofgravity O of the electronic component 18 and is thinner than the flatportion 20. With this configuration, a relatively large impact can bedispersed to the flat portion 20 and a relatively small impact can bedispersed to the slope portion 21. Therefore, it is possible to furtherprevent the damage of the electronic component 18. In the exampleillustrated in FIG. 3, the entire intermediate portion 21 a between theboundary between the flat portion 20 and the slope portion 21 and theposition that overlaps the center of gravity O of the electroniccomponent 18 in the slope portion 21 is thinner than the flat portion20. However, at least a portion of the intermediate portion 21 a may bethinner than the flat portion 20. The thickness of a portion which islocated outside the position that overlaps the center of gravity O ofthe electronic component 18 (on the side opposite to the intermediateportion 21 a) in the slope portion 21 is not particularly limited. Inaddition, the slope portion 21 may be softer than the flat portion 20,that is, the slope portion 21 and the flat portion 20 may be made ofdifferent materials and the Young's modulus of the material forming theslope portion 21 may be relatively small. In this case, a relativelylarge impact can be dispersed to the flat portion 20 and a relativelysmall impact can be dispersed to the slope portion 21. Therefore, it ispossible to further prevent the damage of the electronic component 18.

In an example illustrated in FIG. 5, the flat portion 20 includes a rib22 that protrudes toward the second surface 11 of the supporting member3. The rib 22 is provided so as to be opposite to the center of gravityO of the electronic component 18, with the boundary portion 20 a of theflat portion 20 interposed therebetween. The rib 22 causes the thicknessof the flat portion 20 to be large in the vicinity of the boundaryportion 20 a. With this configuration, a relatively large impact can bedispersed to the flat portion 20 and a relatively small impact can bedispersed to the slope portion 21. Therefore, it is possible to furtherprevent the damage of the electronic component 18. In addition, theweight of the housing 5 can be less than that in a case in which thethickness of the entire flat portion 20 is large and it is possible towiden the arrangement space of the circuit substrate 12 and the powersupply unit 13 (see FIG. 1) provided between the flat portion 20 and thesecond surface 11 of the supporting member 3.

It is preferable that the rib 22 extends along the boundary portion 20 aof the flat portion 20 as illustrated in FIG. 6. It is more preferablethat the rib 22 is formed in a ring shape around the outer periphery ofthe flat portion 20 including the boundary portion 20 a as illustratedin FIG. 7. The impact dispersed to the flat portion 20 is transmittedalong the rib 22, which makes it possible to reduce the impacttransmitted to the central portion of the flat portion 20. Therefore, itis possible to avoid or prevent the transmission of an impact to thecircuit substrate 12 and the power supply unit 13 (see FIG. 1) providedat the position that overlaps the central portion of the flat portion20.

In the above description, the electronic component 18 does not come intocontact with the flat portion 20 and the slope portion 21. However, asillustrated in FIG. 8, the electronic component 18 may come into contactwith the slope portion 21 through a thermal conductor 23 with viscosity.In a case in which the electronic component 18 comes into contact withthe slope portion 21, the impact dispersed to the slope portion 21 canbe transmitted to the electronic component 18. However, the impacttransmitted to the electronic component 18 is absorbed or attenuated bythe viscosity of the thermal conductor 23. Therefore, it is possible toprevent the damage of the electronic component 18. Heat generated fromthe electronic component 18 is transmitted to the slope portion 21through the thermal conductor 23 and is effectively dissipated throughthe housing 5 including the slope portion 21. Therefore, it is possibleto prevent the erroneous operation and damage of the electroniccomponent 18 caused by heat. The thermal conductor 23 with viscosity is,for example, gel in which metal particles, such as aluminum, copper, andsilver particles, or metal oxide particles, such as alumina andmagnesium oxide particles, are dispersed.

In addition, as illustrated in FIG. 9, the electronic component 18 maybe connected to the flat portion 20 through a flexible thermal conductor24. In a case in which the electronic component 18 is connected to theflat portion 20, the impact dispersed to the flat portion 20 can betransmitted to the electronic component 18. However, the impacttransmitted to the electronic component 18 is absorbed or attenuated bythe warpage of the thermal conductor 24. Therefore, it is possible toprevent the damage of the electronic component 18. Heat generated fromthe electronic component 18 is transmitted to the flat portion 20through the thermal conductor 24 and is effectively dissipated throughthe housing 5 including the flat portion 20. Therefore, it is possibleto prevent the erroneous operation and damage of the electroniccomponent 18 caused by heat. The flexible thermal conductor 24 is ametal foil tape such as an aluminum, copper, or silver foil tape.

The reading IC which is an example of the electronic component 18, forexample, includes an integration amplifier for amplifying the signalcharge output from each pixel of the detection substrate 9 and generatesa relatively large amount of heat. The configuration illustrated in FIG.8 which dissipates heat using the thermal conductor 23 with viscosity orthe configuration illustrated in FIG. 9 which dissipates heat using theflexible thermal conductor 24 is particularly useful in a case in whichthe electronic component 18 is a reading IC.

As described above, a radiation detection device disclosed in thespecification comprises: a radiation detection panel; a supportingmember having a first surface on which the radiation detection panel isprovided; an electronic component that is provided on a second surfaceopposite the first surface of the supporting member and drives theradiation detection panel or processes an electric signal output fromthe radiation detection panel; and a housing that accommodates theradiation detection panel, the supporting member, and the electroniccomponent. A bottom of the housing which faces the second surfaceincludes a flat portion and a slope portion that is adjacent to the flatportion and becomes closer to the second surface as becoming furtheraway from the flat portion. The electronic component is provided at aposition where at least a center of gravity of the electronic componentoverlaps the slope portion.

In the radiation detection device disclosed in the specification, theslope portion includes a portion that is provided between a boundarybetween the flat portion and the slope portion and a position thatoverlaps the center of gravity of the electronic component and isthinner than the flat portion.

In the radiation detection device disclosed in the specification, theflat portion includes a rib that protrudes toward the second surface.The rib is provided so as to be opposite to the center of gravity of theelectronic component with the boundary between the flat portion and theslope portion interposed therebetween.

In the radiation detection device disclosed in the specification, therib extends along the boundary between the flat portion and the slopeportion.

In the radiation detection device disclosed in the specification, therib is formed in a ring shape around an outer periphery of the flatportion.

In the radiation detection device disclosed in the specification, theslope portion is softer than the flat portion.

In the radiation detection device disclosed in the specification, theelectronic component does not come into contact with the bottom.

In the radiation detection device disclosed in the specification, theelectronic component comes into contact with the slope portion through athermal conductor with viscosity.

In the radiation detection device disclosed in the specification, theelectronic component is connected to the flat portion through a flexiblethermal conductor.

In the radiation detection device disclosed in the specification, theelectronic component processes the electric signal output from theradiation detection panel.

In addition, the electronic component processes an analog signal.

EXPLANATION OF REFERENCES

1: radiation detection device

2: radiation detection panel

3: supporting member

5: housing

6: top plate of housing

7: transmission plate

8: scintillator

9: detection substrate

10: first surface of supporting member

11: second surface of supporting member

12: circuit substrate

13: power supply unit

14: spacer

15: bottom of housing

16: flexible substrate

17: side portion of housing

18: electronic component

20: flat portion

20 a: boundary portion

21: slope portion

21 a: intermediate portion

22: rib

23: thermal conductor

24: thermal conductor

O: center of gravity

S: installation surface

What is claimed is:
 1. A radiation detection device comprising: aradiation detection panel; a supporting member having a first surfaceand a second surface being opposite to the first surface, wherein theradiation detection panel is provided at a side of the first surface; anelectronic component that is provided on the second surface of thesupporting member and drives the radiation detection panel or processesan electric signal output from the radiation detection panel; and ahousing that accommodates the radiation detection panel, the supportingmember, and the electronic component, wherein a bottom of the housingwhich faces the second surface comprises a flat portion and a slopeportion that is adjacent to the flat portion and becomes closer to thesecond surface as becoming further away from the flat portion, and theelectronic component is provided at a position where at least a centerof gravity of the electronic component overlaps the slope portion whenviewed in a direction perpendicular to the second surface.
 2. Theradiation detection device according to claim 1, wherein the slopeportion comprises a portion that is provided between a boundary betweenthe flat portion and the slope portion and a part of the slope portionthat overlaps the center of gravity of the electronic component whenviewed in the direction perpendicular to the second surface and isthinner than the flat portion.
 3. The radiation detection deviceaccording to claim 2, wherein the slope portion is softer than the flatportion.
 4. The radiation detection device according to claim 2, whereinthe electronic component does not contact with the bottom.
 5. Theradiation detection device according to claim 2, wherein the electroniccomponent contacts with the slope portion through a thermal conductorhaving a viscosity.
 6. The radiation detection device according to claim5, wherein the electronic component processes the electric signal outputfrom the radiation detection panel.
 7. The radiation detection deviceaccording to claim 6, wherein the electronic component processes ananalog signal.
 8. The radiation detection device according to claim 2,wherein the electronic component is connected to the flat portionthrough a flexible thermal conductor.
 9. The radiation detection deviceaccording to claim 8, wherein the electronic component processes theelectric signal output from the radiation detection panel.
 10. Theradiation detection device according to claim 1, wherein the flatportion comprises a rib that protrudes toward the second surface, andthe rib is provided so as to be opposite to the center of gravity of theelectronic component with the boundary between the flat portion and theslope portion interposed therebetween.
 11. The radiation detectiondevice according to claim 10, wherein the rib extends along the boundarybetween the flat portion and the slope portion.
 12. The radiationdetection device according to claim 11, wherein the rib is formed in aring shape around an outer periphery of the flat portion.
 13. Theradiation detection device according to claim 1, wherein the slopeportion is softer than the flat portion.
 14. The radiation detectiondevice according to claim 1, wherein the electronic component does notcontact with the bottom.
 15. The radiation detection device according toclaim 1, wherein the electronic component contacts with the slopeportion through a thermal conductor having a viscosity.
 16. Theradiation detection device according to claim 15, wherein the electroniccomponent processes the electric signal output from the radiationdetection panel.
 17. The radiation detection device according to claim16, wherein the electronic component processes an analog signal.
 18. Theradiation detection device according to claim 1, wherein the electroniccomponent is connected to the flat portion through a flexible thermalconductor.
 19. The radiation detection device according to claim 18,wherein the electronic component processes the electric signal outputfrom the radiation detection panel.
 20. The radiation detection deviceaccording to claim 19, wherein the electronic component processes ananalog signal.